'Minute Mechanical Error' May Have Led to Teen's Remote-Control Helicopter Death, Expert Says

In this image taken from video and provided by WABC-TV in New York, investigators stand near a remote controlled toy helicopter that apparently struck and killed a 19-year-old man Thursday, Sept. 5, 2013, at Calvert Vaux Park in the Brooklyn borough of New York.

The New York teen who died while piloting a remote-controlled helicopter was likely attempting high-speed, freestyle 3-D flying maneuvers and had a mechanical failure with his equipment that led to the fatal crash, according to an expert who viewed a clip the pilot had recently posted online.

Roman Pirozek Jr., 19, died in Brooklyn's Calvert Vaux Park on Thursday when a remote-controlled helicopter he was piloting hit him in the head. A video posted to YouTube in July shows what seems to be Pirozek piloting a T-Rex 700N DFC, which can hold 28-inch main blades that, according to Whey Roberts, an expert on these types of machines, spin at speeds up to 4,000 RPM.

Roberts told ABCNews.com that Pirozek, who was a member of a small group of remote control chopper pilots, was doing some "serious stunts" and he believes it was a problem with the aircraft that led the helicopter to crash and kill the teen.

"There was something wrong with that helicopter," Roberts said. "I've seen many [of Pirozek's] videos -- I was looking at the helicopter as it took off, and had noticed strange oscillation. There was an imbalance somewhere there, something was off slightly. It was minute."

Roberts, who lives in Brooklyn, constructs and sells remote-controlled helicopters as a second income. He said that though Pirozek's skill level was good, nitro fuel powered helicopters have a lot more power, and that he personally won't partake in 3D flying, as it's inherently dangerous.

"They do things that real helicopters can't do," he said. "Flipping around, side-to-side, upside-down. It's really wild, and it takes a good brain for that. No thank you. Regular flight is hard enough as it is."

Even slight mechanical failures, such as a losing the craft's tail rotor, can cause a model aircraft to spin wildly out of control.

The park where Pirozek was piloting his aircraft Thursday was a safe, sanctioned location for flight, designated by New York City as a "model aircraft field." The Academy of Model Aeronautics has a strict set of safety guidelines for pilots that aircraft must not be used in a careless or reckless manner.

But Roberts said that the size of the aircraft made it dangerous to fly 3D maneuvers..

"With helicopters you have to have the utmost concentration," he said. "With planes you can get away with a little bit. With the larger helicopters, you've got to be more mindful of where you are. Anything can happen."

Pirozek's death is said to be only the second such death by remote-controlled helicopter ever in the United States. The Associated Press reported that a few years ago an instructor in Texas was killed by a remote-controlled helicopter after the student he was teaching lost control of it.